Pressure terminology in water mains The maximum pressure that a pipe experiences during normal operation (including expected surges) is called:

Introduction / Context:
Pipeline design uses distinct pressure terms. Confusing them can lead to under- or over-design. Exam questions often ask which term corresponds to the pressure actually seen during service.

Given Data / Assumptions:

• Normal operation of a distribution or transmission main.
• Transient surges are expected within limits but catastrophic water hammer is excluded.

Concept / Approach:

• Working pressure: the maximum service pressure during operation.
• Design pressure: a chosen limit including allowances for surges, used to specify pipe class; sometimes equal to or greater than the working pressure.
• Test pressure: higher hydrostatic pressure applied during commissioning to verify integrity.

Thus, the term corresponding to the maximum during normal operation is “working pressure”.

Step-by-Step Solution:
Identify operational context → not a factory/field test (exclude test pressure).Select the term used for in-service maxima → working pressure.

Verification / Alternative check:
Standards distinguish test pressure (often 1.5 × working) from service conditions; design/class selections are tied to working plus surge criteria.

Why Other Options Are Wrong:

• Design pressure is a specification limit, not necessarily the realized service maximum.
• Test pressure is non-operational and temporary.
• “Pipe pressure” is not a precise technical term; “All the above” cannot be correct.

Common Pitfalls:
Using test-pressure values to size pumps or surge equipment; ignoring surge allowances in setting design class.

Final Answer:
Working pressure